Flushing liquid for cleaning internal-combustion engines



Patented July 2, 1946 FLUSHING LIQUID ron.

' CLEANING mmaNAL-coMBUsn N enemas Robert E. Burk, Cleveland, om, asaignor to The Standard Oil Co notation of Ohio mpany, Cleveland, Ohio, a 001'- No Drawing. Application my 12, 194i, Serial No. 393,135

3 Claims. (01. 252-16l) It is known practice to drain the oil from'internal combustion. engines and then "flush out with kerosene or a light gas oil in an effort to clean out deposited material. Such procedure mechanically sweeps out deposits which are loose or sufficiently quickly softened by the oil. However, an effective cleaning has not been possible in such manner. And, the ability .to loosen and clear deposits of carbonaceous andsludgy substances has remained an important problem in the industry, and to this the presentinvention is directed. 1

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of. the invention may be employed.

In accordance with the invention, an internal combustion engine isdrained of the old oil, and it is then subjected to a surface-active material. This, conveniently may be carried by a free-flowing liquid vehicle, and for compatibility with the lubricating oil normally used. may be a light mineral oil of solvent character or deficient lubricating property, or lacking viscosity such as to afford acceptable lubrication. Thus, a light spindle oil or gas'oil cut rv lighter distillate may be employed for such'vehicle. The surface-active agent is such as to be sufficiently solubleor ,colloidally dispersed in the vehicle and it exerts detergent action. As such surface-active material I employ metallic salts of acids such as higher fatty acids, orvof hydroxy acids, or of synthetic acids from oxidation of a petroleum cut or olefin polymer, or of sulphurized acids of the foregoing or such as unsaturated acids containing one or two double bonds. sulphurized waxes, as degras, or acid radicals of sulphuric ester, sulphonic acids, sulphinic acids, phosphoric or phosphorous esters, etc. The metal may be an alkali metal, especially sodium, alkaline earth metal, as calcium or magnesium, metals of the further periodic groups, as zinc, aluminum, tin, calcium and heavy metals. Generally, .the alkali metals are preferred. The metal salt is'carried in the liquid vehicle in large proportion, such as that it would entirely disqualify the liquid vehicle for lubricant purposes even if. the vehicle had some lubricating viscosity. Thus, amounts of metal salt up to around 15 per cent are desirable, and

this may in instances be less, down to 4 or 5 per To secure as thorough contact as possible of the surfaces and oil passages of the engine where deposits may occur, the material is charged into the :empty oil system of the engine in suitable amount, as for instance an amount corresponding to the heightof lubricating oil normal for the crankcase, orsomewhat less though sufllcient for adequate contacting of the surfaces, and the engine is started and is run for a few minutes, as for instance up to or 20, in order to force the treating material into satisfactory contact with the surfaces to be cleaned. With such brief run, the metal surfaces ofthe engine do not incur any damage, even thoughthe treating materi'al may be corrosive and quite opposed to requirements of lubrication. .Conditioned in this manner, the action is exerted upon the deposited carbonaceous and sludgy substances on the metal, and a relatively vigorous action thereon is had, with softening and weakening .of sludgewithbubble formation, the surface-active agent resin binder and the freeing of carbonaceous particles. Even if air be beaten into the liquid,

' further assists at the air-liquid interface by particularly suspending carbon particles. Thus, such surface-active materials as for instance sodium or potassium stearate or of other higher.

fatty acid, or of esters of sulphoorganic acids of high molecular weight, as sulphates or sulphonates, as sodium lauryl sulphate, etc., soaps vof sulphurized degras, etc. are desirable. In

some cases cleaning action on the metal may be furthered also by inclusion of a material active on metal, such as semi-neutralized unsaponiiied fat or wax which has been treated with phosphorus pentasulphide, or an unsaturated polymer such a polypropylene treated with a phosphorus pentasulphide, or a nitrogen compound such as tetramethyldiaminodiphenylmethane, or

with P285 to the take-up offive per cent or more.

of sulphur and then neutralizing with caustic soda, is stirred, to the amount of about 10 per agcoaica.

cent, into gas oil. The engine to cleaned is drained of its lubricating Oil, and this liquid is charged into the crankcase and the en ine is started and is run for about ten minutes. The

liquid is thoroughly drained out, and after then filling up with lubricating oil, the engine is rea y for service.

Other modes of applying the principle of the I therefore particularly point out and distinctly claim as my invention:

1. A flushing liquid for cleaning internal'co bustion engines, comprising at least four per cent of a metal salt of the reaction product of degras I j and phosphorus pentasulphide, and a semi-neu- Y tralized unsaponifled tat which has been treated with phosphorus pentasulphide, in a liquid vehicle consisting of a light mineral oil distillate of 1 invention may-be employed, change being made a as regards the .details described, provided the features stated in any oi the following claims,

or the equivalent of such, be employed.

a of a metal salt of the reaction product-of degras and phosphorus pentasulflde, and a semi-neutralized unsaponiiied fatty acid ester which has been treated with phosphorus pentasulflde, in a liquid vehicle consisting of a light mineral oil distillate oi deficient lubricating property and of viscosity not greater thanthat 01 light spindle oil;

3. A flushing liquid for cleaning internal combustion engines, comprising at least four per cent I of a metal salt of the reaction product or degras and phosphorus pentasulphide, in a liquid vehicle consisting of a light mineral oil distillate oi deficient-lubricating property andvoi viscosity not greater than that of light spindle oil.

aosna'r E. BURK. 

